SU721707A1 - Device for determining printing ink yielding - Google Patents

Description

I

The invention relates to the printing industry, mainly to printing processes, and can be used to determine the quality of offset and letterpress prints.

In modern printing processes, the quality of printed products depends on the rheological properties of inks. These properties of paints are judged either by spreading a drop of paint under pressure or on the basis of viscosity measurements on various types of viscometers.

A device for detecting the spreading of a drop in the form of a form on which a drop of the test substance 1 is placed is known.

This device does not allow to establish the nature of the deformation of thin layers of paint at the time of printing.

The closest technical solution to the present invention is a device for detecting the spreading of printing ink, including a mold and a piston, which exerts pressure on a drop of ink that is placed on the mold 2.

This device does not allow to establish the nature of the deformation of thin layers of paint.

(thickness from 1 to 8 µm) with a varying pressure and time of its action, and provides only a maximum spreading index (diameter of a spreading spot). In addition, a sample of paint in its form does not match the paint layer, distributed on the printing form and print.

As a result of using this device, it is not possible to establish the kinetics of ink flow on the printing elements of the form.

As a result, the dynamics of the ink transfer process on the forms and prints of offset and letterpress remain undisclosed, which makes it impossible to establish practical recommendations on conditions that ensure uniform distribution of ink in order to obtain higher quality printing products.

The aim of the invention is to improve the accuracy of the spreading and the quality of the prints obtained.

Claims (2)

This is achieved by the fact that the proposed device additionally contains a disk connected to the feed screw, an elastic ring, a transparent glass located above the form, and an indicator, the elastic ring being pivotally connected in the upper part to the piston, to the lower part to the feeding screw. at the end of the elastic ring. The drawing shows the proposed device. The device for detecting the spreading of the ink has a plate 1 to which the screws 3 secure the base 3. In turn, the base is fastened with screws 4 to the stand 5. In the base cavity there is a disk 6 connected by thread with feed BINT 7 that can be moved inside the through hole of the base. The screw head 7 is connected by a pin 8 to the lower part of the elastic ring 9. The upper part of the elastic ring is also connected by a pin to the piston 10 sliding inside the rack 5. To the upper part of the rack 5 screws 11 fix the cover 12 having a through viewing window. The slurry 10 has a recess for installing a form-holder therein, in which the mold 13 is placed. In the lining 12 a horizontal through rectangular groove is cut into which a rigid transparent plate 14 is installed, limiting the movement of the piston with the mold 13. To measure the pressure on the elastic ring 9 with screws 15, the indicator 16 is fixed and the stop 17, which restricts the movement of the legs 18 of the indicator 16. The device works as follows when the disk 6 is rotated clockwise, the feed screw 7 rises and compresses the elastic ring 9, which In turn, the spraying 10 moves upwards. The crush 10 has a spherical recess on the upper end, which allows the mold holder 19 with the mold 13 to be positioned in it to take a position strictly parallel to the plate 14. For this, there is a landing ball on the mold holder 19. When the piston is moved, the ink layer deposited on the mold comes in contact with a rigid transparent plate 14, which can serve as a printing material (or on the lower surface of which you can fix the required, but also transparent material). If the material being printed is opaque, it is placed instead of form on form holder 19, and the form (transparent and rigid) is set instead of plate 14. In any case, the pressure generated is fixed by an arrow indicator 16, which is tared from a known load value. The device allows, with recalculation to the area of the form, to set pressures within O-60 kgf / cm, which corresponds to the actual pressures of the printing process. Observation (or photographing and filming), as well as measuring the kinetics of ink spreading on the material being printed and the form, is made through the viewing window of the lining 12 using a measuring microscope equipped with an eyepiece with a micrometer. The use of the proposed device for determining the spreading of printing ink provides the following advantages: it provides the possibility of determining, based on the study of the kinetics of spreading, the rheological properties of thin layers of printing ink; allows you to choose paints that differ in the most uniform distribution on various printed materials; provides the ability to determine the spreading of ink on the printed material using forms with different area and configuration of the printing elements; It allows to determine the influence of pressures on the nature of the spreading of the paint distribution in the zone of contact of the mold with the material to be printed, which improves the quality of the prints and their cost. Apparatus for detecting the spreading of printing ink, including the form and the piston, characterized in that, in order to improve the accuracy of determining the spreading and the quality of the printed impressions, it additionally contains a disk connected to the feed screw, an elastic ring, a transparent glass located above the form, and an indicator, the elastic ring being pivotally connected in the upper part with the piston, in the lower part with the feed screw, and the indicator is fixed at the end of the elastic ring, the sources of information taken into account when ek examinations of 1.Zimok AD .gezi liquids and wetting. M., “Himi, 1974, p. 129-140. 2. Zagarniska L. and others. Printing materials. M., 1964, p. 847 (prototype).